【摘要】 目的建立一种树脂富集-石墨炉原子吸收直接测定食品中六价铬的方法。方法市售大米样品滤过强碱性离子交换树脂分离富集六价铬,通过洗脱剂洗脱,石墨炉原子吸收法直接测定洗脱液中六价铬的含量,探究影响离子交换的各种因素,分析并筛选最佳洗脱条件和离子交换树脂分离富集的最佳条件,以回收率作为筛选各项最优因素的指标。结果 15 ml的2.0 mol/L的NH4NO3溶液为最佳洗脱条件,当溶液pH值为3时是离子交换树脂分离富集最佳条件,应用10 ml的稀硫酸溶液(pH值为4)淋洗离子交换树脂柱对六价格的分离富集影响最少。六价铬回收率为95.4%~97.7%之间,精密度RSD为0.99%。结论本实验方法简便、快速、检测方法准确、灵敏度和精密度高,适用于食品中的六价铬的直接测定。。更多还原

【Abstract】 Objective To establish a method for direct determination of hexavalent chromium in foods by resin enrichment-graphite furnace atomic absorption spectrometry. Methods Hexavalent chromium was separated and concentrated by strong base anion exchange resin from commercially available rice sample,then desorped by eluent,and finally determined by graphite furnace atomic absorption spectrometry. The various influencing factors of ion exchange were explored and analyzed to select the optimal elution conditions and the best condition for separation and enrichment of hexavalent chromium on resin exchange,taking recovery as the optimal screening factor. Results Ammonium nitrate solution of 2. 0 mol / L in 15ml was taken as the optimum conditions for elution. The optimum conditions for separation and enrichment of ion exchange resin were set at room temperature(20 ℃) and pH 3. 0. Dilute sulfuric acid solution of pH 4. 0 in 10 ml showed the least influence on separation and enrichment of hexavalent chromium by ion exchange resin. The standard recovery rate of hexavalent chromium was between 95. 4% ~ 97. 7%,with RSD of 0. 99%. Conclusion This method has the advantages of convenience,fleetness,accuracy,high sensitivity and precision. It was suitable for the direct determination of hexavalent chromium in foods.更多还原